The present invention relates to a manufacturing method for a motor driving device and a motor driving device manufactured using this manufacturing method.
Hybrid vehicles with an engine and a motor driving device as drive sources have gained attention with respect to fuel efficiency, environmental protection, and so on. In the hybrid vehicles, the motor driving device acts as a motor that obtains power from a battery in order to generate a driving force, and transmits the driving force to a running mechanism side, to thereby cause the vehicle to run on the motor. The motor driving device may also act as a generator that obtains a driving force from the engine and uses this driving force to charge the battery. The motor driving device also performs a so-called regeneration operation in which the surplus inertial force of the vehicle is collected as power during braking. The motor driving device may also be used during engine start-up.
Accordingly, a rotor of the motor driving device provided in a hybrid vehicle is drivingly connected to a speed change mechanism side and an engine side to enable transfer of the driving force.
The motor driving device includes a stator and the rotor housed inside the stator, and the stator and rotor are supported from a motor case side. The stator is fixedly supported, whereas the rotor is rotatably supported from a shaft-support portion provided in the motor case. In a hybrid vehicle, the motor case is rarely provided separately, and typically a part of a transmission case housing the speed change mechanism in its interior doubles as the motor case.
In the motor driving device, the gap and concentricity between the stator and rotor are extremely important elements for determining the performance of the motor driving device, and are therefore managed and adjusted strictly.
Japanese Patent Application Publication No. JP-A-7-241050 discloses a technique for performing this type of adjustment. This technique relates to a gap adjustment device for an electric automobile motor that adjusts the gap by providing adjusting bolts in an upright manner in a flywheel housing (equivalent to the motor case described heretofore), and adjusts an outer peripheral location of a stator core. A stator in this example is comparatively thin. In other words, the stator thickness in the direction of a rotary axis (which shares an axial center with the stator) of the rotor is comparatively small.